An effective approach to produce a nanocrystalline Ni–Ti shape memory alloy without severe plastic deformation

Bulk nanocrystalline ( d = 20–40 nm) Ni–Ti shape memory alloy was produced via cold marforming, followed by optimum post-heat treatment. The total accumulative strain ( e ∼ 0.7) during the process was much lower than that typically imposed during severe plastic deformation operations (i.e., 5 ≤ e ≤ 12). In-situ heating transmission electron microscopy revealed that the present process was effective in promoting static recrystallization and limiting grain growth. The nanocrystalline alloy exhibited enhanced shape memory behaviors.